High-efficiency Drive Technology for High-speed, Multi-pole Motors with Minor Sampling Process

Permanent magnet synchronous motors are characterized by their compact size and high efficiency. They are increasingly becoming high-speed, multi-pole motors in response to the demand for higher power density. With higher speeds and multipoles, the drive frequency of motors increases, and iron loss tends to increase. Increased iron loss leads to current detection errors, which may cause a decrease in efficiency. This paper proposes a new method of three-shunt current detection using minor sampling, considering the influence of current detection errors due to iron loss. In addition, to improve the detection accuracy of the proposed method, a method to suppress the detection error is devised. Experiment results show that the proposed method worked stably even with an RC filter inserted, and the effectiveness of the proposed method was confirmed experimentally.